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Pulling the Lower Manifold

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fords4life

Pulling the Lower Manifold

Planning to pull the lower manifold this weekend and the valve covers to reseal everything. Have an oil leak that I'm pretty confident is the lower manifold and not a rear main. Since I've never pulled one on these motors before, thought I'd check to see if I have everything covered.

Gaskets - Complete Set for Manifolds and Valve Covers
Grey RTV Silicone for front and rear of valley
ACT
Oil Pressure Sender
Coolant Temp Sender
Coolant Temp Switch
Thermostat
Thermostat Housing
Lower Manifold Bolts
Coolant
Spark Plugs(also plan to check compression while I'm at it.)
Distributor O-Ring
Injector O-Rings just in case
Plan to re-use the upper manifold bolts
Paint for Valve Covers and Manifolds if I get adventurous

I think that covers everything I've got. Are there any o-rings for the quick connect fittings where the fuel lines connect to the fuel rail that I need?

Any other thoughts or things I should check while I'm in that deep?

1986 F-150 SC 2wd 4spd 302EFI Base Model all OEM motor/trans/emissions equipment.

Gary Lewis

Re: Pulling the Lower Manifold

Administrator

That's a pretty comprehensive list. But, I'm not sure you need to replace all of those things. For instance, the ACT, oil pressure sender, coolant sender and switch, and lower manifold bolts could be re-used unless you already were having problems. But, it shouldn't hurt to replace them.

As for o-rings or gaskets on the fuel lines, I don't see them in the illustration here: Fuel Systems/Fuel System Illustrations/F-Series 302 w/EFI.

But, I'm not a fan of compression testing. Or, maybe I should say that it can have very misleading results. Instead, I much prefer leak-down testing. If you have a source of compressed air this test will show you how well the rings are sealing, if you have head gasket problems, cracks in the head or block, or valves leaking.

Maybe I should write up a page on what leak-down testing is and how to do it. But there are other pages on the internet that explain it fairly well, so you can check that out if you are interested.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

ArdWrknTrk

Re: Pulling the Lower Manifold

Administrator

In reply to this post by fords4life

Do you have a long bit to remove the fun little fastener you can only reach between the runners?

Not sure the size but it seems like a good tool to have if you own one of these vehicles.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

sgauvry

Re: Pulling the Lower Manifold

In reply to this post by fords4life

I think Gary answered your question well. Don't spend money on new sensors unless you're certain you need to. On the other hand, I recently replaced all of my sensors, but I also replaced the entire engine and wanted everything new.

With regard to the fuel line connections, if you have quick connect originals, there are no "O" rings to purchase. What you have will do the job.

Steven A. Gauvry - 1985 F150 5.0 EFI

myrl883

Re: Pulling the Lower Manifold

The tool for the bolt that ArdWrknTrk mentioned has to be 1/4" drive to fit between the runners. Harbor Freight is your friend here.
Also, be careful with the lower manifold bolts, the end bolts near the coolant crossovers tend to corrode and are very easy to break - and can be hard to extract from the heads.

Ford Parts Monkey since 1985
1981 F100 Flareside - Black, 302-4V Roller/AOD
1986 F150 Flareside - Medium Fire Red 302/AOD
1989 F150 Standard Cab 4x4 - Dk Shadow Blue 302/AOD
1993 F350 4x4 Crew Cab - 7.3 IDI/ZF-5
I think it's a sickness...

fords4life

Re: Pulling the Lower Manifold

Thanks for the responses. As far as I know all the sensors are working correctly, but I'm pretty confident that all of them are original. I tend to go a little overboard, but since it's all coming out anyway, it's easier to replace them now and be done with it.

As for the long extension, no problems there. I have a pretty good selection of tools and plenty of extensions.

I will pay a little more attention to the end bolts for sure.

Forgot to mention the PCV which is getting replaced as well. I also bought some threaded rod to make studs for the ends of the manifolds so I can guide it down straight and have less chance of messing up the RTV on the ends.

I know what you mean by leak down test. I'll do some research and see if I can find some info on how much pressure to start with and how much you can lose over time. I would imagine it takes quite a bit more time to do a leak down vs. the compression test.

1986 F-150 SC 2wd 4spd 302EFI Base Model all OEM motor/trans/emissions equipment.

Gary Lewis

Re: Pulling the Lower Manifold

Administrator

I like long bolts with the heads cut off instead of all-thread to guide my manifold on with as the smooth bolts make things slide easier. But, if you are careful all-thread will work.

As for a leak-down test, I like to use 100 psi as then whatever pressure the second gauge reads is the same as percentage. IOW, if you start with 100 and have 90 on the 2nd gauge you have 10% loss.

And that really doesn't take any more time than a compression test. Except, if you have a lot of leakage then you have to start listening to see where the leaks are going. And listening in the intake, exhaust, and looking in the cooling system does take a bit more time. But well worth it.

Gary, AKA "Gary fellow": Profile

ArdWrknTrk

Re: Pulling the Lower Manifold

Administrator

In reply to this post by fords4life

Sometimes I think it's better to just have a really long T40 bit than to tape a T40 socket to a 1/4" extension.

But that's just me...
I notice that I still have a Honda cylinder head tool (8pt, 10mm?) from the early '80's kicking around in my tool box.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

fords4life

Re: Pulling the Lower Manifold

Glad you mentioned the T40 bit. I haven't looked close enough yet to see what sockets are required. I know I have torx bits that size, but not sure what drive they are. I will take a look.

I know Gary has mentioned port matching the lower manifold to the head. I have port matched to the gaskets before, but how do you guys transfer the head port size(which is usually smaller than the gasket) to the lower manifold? Or do you just match it to the manifold?

Thanks Again for the feedback!

1986 F-150 SC 2wd 4spd 302EFI Base Model all OEM motor/trans/emissions equipment.

Gary Lewis

Re: Pulling the Lower Manifold

Administrator

My understanding is that you don't want the manifold to be larger than the head as that causes turbulence and slows the flow. But it is ok for the manifold to be smaller than the head.

I've used the gasket as the standard, and opened up to match it. I paint the head with bluing, put the gasket on, and scribe a line. Then port out to that.

Gary, AKA "Gary fellow": Profile

fords4life

Re: Pulling the Lower Manifold

Gary - I completely agree on the manifold ports needing to be the same size or smaller than the head ports. I can mark the heads with the head gaskets and the manifold with the gasket, but since the heads are on the motor and I can't port match those right now. Trying to figure out the easiest way to transfer the head port sizes over the manifold.

1986 F-150 SC 2wd 4spd 302EFI Base Model all OEM motor/trans/emissions equipment.

Gary Lewis

Re: Pulling the Lower Manifold

Administrator

Oh! Duh!

Now I understand the question. Can you put heavy paper against the head, held on with bolts in the bolt holes, and gently cut it out to match the head?

Gary, AKA "Gary fellow": Profile

ArdWrknTrk

Re: Pulling the Lower Manifold

Administrator

Grease or paint on the head surfaces will transfer to the lower?
There will be some misalignment because of the missing gasket thickness.

Back in the day we would use pizza box for templates like this.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.